Optimism Bias — The Illusion That 'I'll Be the Exception'
'I know it's risky on average, but it won't happen to me.' Most of us have thought this at some point. The problem is that almost everyone believes it.
What Optimism Bias Is
Optimism bias is the tendency to estimate the probability of good things happening to oneself as higher than it really is, and the probability of bad things as lower than it really is.
The neuroscientist Tali Sharot called this 'one of the greatest illusions the human mind commits.' Classic examples are smokers who feel they personally won't get sick, and most founders who believe 'my business will succeed.' Statistically, the majority must be below average, yet people place themselves above it.
Optimism Bias in Investing
Optimism bias dulls risk management.
Baseless confidence like 'others may get trapped at the top, but I'll get out in time' or 'this stock is different' is typical. As a result, people invest everything without an emergency fund, use leverage they can't handle, or fail to prepare for the worst-case scenario.
Especially when a bull market runs long, optimism bias strengthens, and the moment everyone believes 'this time it's different' is dangerous. Optimism bias is also a core component of overconfidence.
How to Manage Optimism
Optimism itself is a driving force in life and doesn't need to be eliminated. But when it comes to money, it's safer to plan on the premise that 'I'm not an exception either.'
Specifically, a 'pre-mortem' — writing out the worst-case scenario first — is useful. Imagining 'if this investment failed completely, what would have caused it?' in advance makes your preparation more thorough.
This is also why this site always shows maximum drawdown and loss periods alongside returns. Instead of imagining only good outcomes, accepting in advance that 'this asset once fell as much as -50%' raises the odds that you'll actually endure that stretch.
Frequently Asked Questions
Q. How is optimism bias different from overconfidence?
Optimism bias is expecting the 'future outcome' to be good, while overconfidence is overestimating the 'accuracy of your own judgment and knowledge.' The two often appear together. If you're optimistic about the future and also overconfident in your own ability, you underestimate risk twice over.
Q. Is it advantageous for investing to eliminate optimism bias?
It's hard to eliminate completely, and excessive pessimism keeps you from investing at all, causing you to miss the chance for long-term compounding. The goal is not removal but balance. Over the long run, it's realistic to stay optimistically in the market while handling risk management and worst-case preparation with a cool head.
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